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Differentiating atypical lipomatous tumors (ALTs) and well-differentiated liposarcomas (WDLs) from benign lipomatous lesions is important for guiding clinical management, though conventional visual analysis of these lesions is challenging due to overlap of imaging features. Radiomics-based approaches may serve as a promising alternative and/or supplementary diagnostic approach to conventional imaging.The purpose of this study is to review the practice of radiomics-based imaging and systematically evaluate the literature available for studies evaluating radiomics applied to differentiating ALTs/WDLs from benign lipomas.A background review of the radiomic workflow is provided, outlining the steps of image acquisition, segmentation, feature extraction, and model development. Subsequently, a systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the grey literature was performed from inception to June 2022 to identify size studies using radiomics for differentiating ALTs/WDLs from benign lipomas. Radiomic models were shown to outperform conventional analysis in all but one model with a sensitivity ranging from 68 to 100% and a specificity ranging from 84 to 100%. However, current approaches rely on user input and no studies used a fully automated method for segmentation, contributing to interobserver variability and decreasing time efficiency.Radiomic models may show improved performance for differentiating ALTs/WDLs from benign lipomas compared to conventional analysis. However, considerable variability between radiomic approaches exists and future studies evaluating a standardized radiomic model with a multi-institutional study design and preferably fully automated segmentation software are needed before clinical application can be more broadly considered.

The 2018 ovarian-adnexal reporting and data system (O-RADS) guidelines are aimed at providing a system for consistent reports and risk stratification for ovarian lesions found on ultrasound. It provides key characteristics and findings for lesions, a lexicon of descriptors to communicate findings, and risk characterization and associated follow-up recommendation guidelines. However, the O-RADS guidelines have not been validated in North American institutions or amongst less experienced readers.To evaluate the diagnostic accuracy and inter-reader reliability of ultrasound O-RADS risk stratification amongst less experienced readers in a North American institution with and without pre-test training.A single-center retrospective study was performed using 100 ovarian/adnexal lesions of varying O-RADS scores. Of these cases, 50 were allotted to a training cohort and 50 to a testing cohortMean patient age was 40 ± 16 years with lesions ranging from 1.2 to 22.5 cm. Readers demonstrated excellent specificities (85%-100% pre-training and 91%-100% post-training) and NPVs (89%-100% pre-training and 91-100% post-training) across the O-RADS categories. Sensitivities were variable (55%-100% pre-training and 64%-100% post-training) with malignant O-RADS 4 and 5 Lesions pre-training and post-training AUC values of 0.87-0.95 and 0.94-098, respectively (Less experienced readers in North America achieved excellent specificities and AUC values with very good pairwise inter-reader reliability. They may be subject to misclassification of potentially malignant lesions, and specific training around dermoid features and smooth

99mTc-sestamibi SPECT/CT is a promising nuclear medicine imaging investigation for benign renal lesions such as renal oncocytomas. The purpose of this article is to i) review the current literature on 99mTc-sestamibi SPECT/CT, ii) to review to current application of 99mTc-sestamibi SPECT/CT for indeterminate renal lesion imaging, and iii) to discuss present limitations and areas for future research. The literature has been reviewed up to April 2022 for articles relating to the application of 99mTc-sestamibi SPECT/CT for benign renal lesions including a recently published systematic review and meta-analysis performed by the authors. One study evaluating 99mTc-sestamibi SPECT alone and five studies evaluating 99mTc-sestamibi SPECT/CT have been performed to date. 99mTc-sestamibi SPECT/CT demonstrates high sensitivity and specificity for detecting benign renal lesions, particularly renal oncocytomas. 99mTc-sestamibi SPECT/CT demonstrates near-perfect specificity for benign and low-grade renal lesions. The optimal quantified threshold ratio for tumor-to-background renal parenchyma radiotracer uptake for a positive result is > 0.6. In this article, we propose a modified diagnostic algorithm for small enhancing renal masses measuring 1-4 cm in which suspected benign lesions after conventional imaging are considered for 99mTc-sestamibi SPECT-CT. In this algorithm, positive studies can be monitored with active surveillance rather than requiring invasive biopsy and/or targeted therapy.

BACKGROUND The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) was introduced to standardize the ultrasound characterization of thyroid nodules. Studies have shown that ACR-TIRADS reduces unnecessary biopsies and improves consistency of imaging recommendations. Despite its widespread adoption, there are few studies to date assessing the inter-reader agreement amongst radiology trainees with limited ultrasound experience. We hypothesize that in PGY-4 radiology residents with no prior exposure to ACR TI-RADS, a statistically significant improvement in inter-reader reliability can be achieved with a one hour training session. AIM To evaluate the inter-reader agreement of radiology residents in using ACR TI-RADS before and after training. METHODS A single center retrospective cohort study evaluating 50 thyroid nodules in 40 patients of varying TI-RADS levels was performed. Reference standard TI-RADS scores were established through a consensus panel of three fellowship-trained staff radiologists with between 1 and 14 years of clinical experience each. Three PGY-4 radiology residents (trainees) were selected as blinded readers for this study. Each trainee had between 4 to 5 mo of designated ultrasound training. No trainee had received specialized TI-RADS training prior to this study. Each of the readers independently reviewed the 50 testing cases and assigned a TI-RADS score to each case before and after TI-RADS training performed 6 wk apart. Fleiss kappa was used to measure the pooled inter-reader agreement. The relative diagnostic performance of readers, pre- and post-training, when compared against the reference standard. RESULTS There were 33 females and 7 males with a mean age of 56.6 ± 13.6 years. The mean nodule size was 19 ± 14 mm (range from 5 to 63 mm). A statistically significant superior inter-reader agreement was found on the post-training assessment compared to the pre-training assessment for the following variables: 1. “Shape” (k of 0.09 [slight] pre-training vs 0.67 [substantial] post-training, P < 0.001), 2. “Echogenic foci” (k of 0.28 [fair] pre-training vs 0.45 [moderate] post-training, P = 0.004), 3. ‘TI-RADS level’ (k of 0.14 [slight] pre-training vs 0.36 [fair] post-training, P < 0.001) and 4. ‘Recommendations’ (k of 0.36 [fair] pre-training vs 0.50 [moderate] post-training, P = 0.02). No significant differences between the pre- and post-training assessments were found for the variables 'composition', 'echogenicity' and 'margins'. There was a general trend towards improved pooled sensitivity with TI-RADS levels 1 to 4 for the post-training assessment while the pooled specificity was relatively high (76.6%-96.8%) for all TI-RADS level. CONCLUSION Statistically significant improvement in inter-reader agreement in the assigning TI-RADS level and recommendations after training is observed. Our study supports the use of dedicated ACR TI-RADS training in radiology residents.

This systematic review and meta-analysis evaluated the diagnostic accuracy of dual-energy CT (DECT) for detecting bone marrow edema (BME) in adult patients with acute knee injuries. A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and gray literature was performed from inception to January 31, 2020, using PRISMA-DTA guidelines. The review included studies assessing the diagnostic accuracy of DECT for detecting BME in at least 10 adult patients with acute knee injuries and with an MRI reference standard. Study details were independently extracted by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model with subgroup analysis performed to evaluate for sources of variability. Risk of bias (ROB) was evaluated using the QUADAS-2 tool. Eight studies evaluating 267 patients between the ages of 25–54 with acute knee injuries undergoing DECT and MRI were included in analysis. Summary sensitivity, specificity, and AUROC values for BME were 84% (95% confidence interval (CI) 74–91%), 96% (95% CI 93–98%), and 0.97 (95% CI 0.95–0.98), respectively. Bone-based characterization was found to have lower specificity than region-based characterization (83% (57–95%) versus 97 (96–98%), p

Background Lipid-poor angiomyolipomas (AMLs) are challenging to differentiate from other renal lesions at imaging and often necessitate biopsy or surgery. If sufficiently accurate, MRI may play a role as a replacement test for biopsy. Purpose To perform a systematic review to evaluate the diagnostic performance of MRI for lipid-poor AMLs in patients with renal masses. Materials and Methods A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the "gray literature" (conference proceedings) was performed without language restriction through July 18, 2019, with the assistance of a health sciences librarian. Original articles with more than 10 patients evaluating the diagnostic performance of MRI, with histopathologic findings used as the reference standard, for the diagnosis of lipid-poor AMLs in patients with renal masses were included. Studies including AMLs with macroscopic fat and studies with insufficient data were excluded. Patient, clinical, MRI, and diagnostic performance parameters were independently acquired by two authors. Meta-analysis was performed by using a random-effects or bivariate mixed-effects regression model depending on the number of studies. Risk of bias of individual studies was evaluated by using Quality Assessment of Diagnostic Accuracy Studies-2. Results Twenty-three studies with 2196 patients and 25 contingency tables were included. The pooled sensitivity, specificity, and area under the receiver operating characteristic curve were 83% (95% confidence interval [CI]: 72%, 90%), 90% (95% CI: 84%, 94%), and 0.93 (95% CI: 0.91, 0.95), respectively. Considerable variability was present for several variables, including MRI parameters; however, subgroup analysis did not identify MRI sequence or field strength as sources for variability. All studies were at high risk of bias for index test domain because no reported thresholds were prespecified. Conclusion MRI shows promising accuracy for detecting lipid-poor angiomyolipomas (area under the receiver operating characteristic curve, >0.9), indicating a potential role as a replacement test for biopsy in selected patients. Studies evaluating MRI accuracy with a pragmatic algorithm and prespecified threshold may be helpful to confirm this potential role in the management pathway. © RSNA, 2020 Online supplemental material is available for this article.

The suprarenal retroperitoneum and adrenal gland is a rare site of origin for benign schwannomas which frequently present as larger and more aggressive lesions than schwannomas identified elsewhere. These tumors are often surgically excised. We present a case of an 81-year-old asymptomatic man presenting with an incidental 10 cm left suprarenal retroperitoneal mass identified on CT. The mass was indiscernible from the adrenal gland, demonstrating heterogeneous enhancement with a centrally cystic/necrotic core, and punctate calcifications. Subsequent core needle biopsy demonstrated a benign adrenal schwannoma. The lesion has been managed conservatively with imaging follow up and without complication. DISCUSSION: Our review of the literature identifies 121 reported in vivo benign adrenal and suprarenal schwannomas published to date with imaging features available for 90 cases (74%). All cases were encapsulated with the average size measuring over 6.5 cm. Fifteen percent (13/84) of reported lesions measured over 10 cm at presentation. Punctate calcification was present in 50% (26/52) of reporting cases. Nearly 50% (40/86) of cases demonstrate cystic/necrotic appearances on imaging. Despite aggressive appearances, our case demonstrates that biopsy and surveillance may represent a reasonable alternative to surgery in suboptimal surgical candidates.

The primary objectives of this systematic review and meta-analysis were to evaluate the diagnostic accuracy of 99mTc-sestamibi SPECT/CT for detecting renal oncocytoma versus (1) all other renal lesions and (2) chromophobe renal cell carcinoma (ChrRCC) alone. A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the Gray Literature was performed. Original articles with > 5 patients evaluating oncocytomas versus other renal lesions with SPECT/CT using a pathological reference standard were included. Patient, clinical, imaging, and performance parameters were independently acquired by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model. Four articles with a total of 117 renal lesions were included in analysis. The pooled and weighted sensitivity and specificity values of 99mTc-sestamibi SPECT/CT for detecting (1) renal oncocytoma versus other renal lesions were 92% (95% CI 72–98%) and 88% (95% CI 79–94%), respectively, and (2) 89% and 67%, respectively, for renal oncocytoma versus ChrRCC. The specificity for the detecting the oncocytoma-ChrRCC spectrum was 96% (95% CI 84–99%). The sensitivity and specificity for detecting benign versus malignant renal lesions were 86% (95% CI 66–95%) and 90% (95% CI 80–95%), and 88% and 95% when HOCTs were characterized as benign. All reporting studies used a cut-off tumor-to-background renal parenchyma radiotracer uptake ratio of > 0.6 for positive studies. 99mTc-sestamibi SPECT/CT demonstrates a high sensitivity and specificity for characterizing benign and low-grade renal lesions. This test can help improve the diagnostic confidence for patients with indeterminate renal masses being considered for active surveillance.

Background: Radiology interest groups (RIGs) can serve as a means of increasing exposure of the radiology specialty early in the medical curriculum while also increasing educational opportunities. However, the organizational structure and various functions of individual RIGs in Canada are not well-documented. We performed a survey of all active RIGs in Canada for the purpose of better understanding their structure, function, and opportunities for improvement. Methods: A 21-question survey was sent to current or recent former medical student leaders of all active RIGs in Canada during the 2016-2017 academic year. Results: Radiology interest groups were identified in 88% (15/17) of Canadian medical schools. We received a 100% (15/15) response rate. Events held by RIGs consist mostly of lunch and learns (67%, 10/15), career panels (53%, 8/15), networking events (40%, 6/15), and curriculum-related events (40%, 6/15). General mentorship (93%, 13/14), shadowing opportunities (86%, 12/14), and research mentorship (63%, 8/14) were most often cited in their top 3 choices for opportunities for improvement. Sixty-six percent indicated that if a radiology society were to host a page for their interest group, they would be interested in posting content and/or links. Conclusions: Canadian RIGs offer increased early awareness and education about radiology in the medical curriculum. Radiology departments can facilitate improvement in Canadian RIGs through targeted institutional mentorship, research opportunities, and shadowing programs for their members.

Background: Hepatocellular carcinoma (HCC) can be diagnosed non-invasively, provided certain imaging criteria are met. However, the recent Liver Imaging Reporting and Data System (LI-RADS) version 2018 has not been widely validated.Objectives: This study aimed to evaluate the diagnostic accuracy and reader reliability of the LI-RADS version 2018 lexicon amongst fellowship trained radiologists compared with an expert consensus reference standard.Method: This retrospective study was conducted between 2018 and 2020. A total of 50 contrast enhanced liver magnetic resonance imaging (MRI) studies evaluating focal liver observations in patients with cirrhosis, hepatitis B virus (HBV) or prior HCC were acquired. The standard of reference was a consensus review by three fellowship-trained radiologists. Diagnostic accuracy including sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) and area under the curve (AUC) values were calculated per LI-RADS category for each reader. Kappa statistics were used to measure reader agreement.Results: Readers demonstrated excellent specificities (88% – 100%) and NPVs (85% – 100%) across all LI-RADS categories. Sensitivities were variable, ranging from 67% to 83% for LI-RADS 1, 29% to 43% for LI-RADS 2, 100% for LI-RADS 3, 70% to 80% for LI-RADS 4 and 80% to 84% for LI-RADS 5. Readers showed excellent accuracy for differentiating benign and malignant liver lesions with AUC values > 0.90. Overall inter-reader agreement was ‘good’ (kappa = 0.76, p < 0.001). Pairwise inter-reader agreement was ‘very good’ (kappa ≥ 0.90, p < 0.001).Conclusion: The LI-RADS version 2018 demonstrates excellent specificity, NPV and AUC values for risk stratification of liver observations by radiologists. Liver Imaging Reporting and Data System can reliably differentiate benign from malignant lesions when used in conjunction with corresponding LI-RADS management recommendations.

OBJECTIVEFreehand insertion of external ventricular drains (EVDs) using anatomical landmarks is considered the primary method for placement, although alternative techniques have shown improved accuracy in positioning. The purpose of this study was to retrospectively evaluate which features of the baseline clinical history and preprocedural CT scan predict EVD positioning into suboptimal and unsatisfactory locations when using the freehand insertion technique.METHODSA retrospective chart review was performed evaluating 189 consecutive adult patients who received an EVD via freehand technique through an anterior burr hole between January 1, 2014, and December 31, 2015, at a Level 1 trauma facility in Edmonton, Alberta, Canada. The primary outcome measures included features associated with suboptimal positioning (Kakarla grade 1 vs Kakarla grades 2 and 3). The secondary outcome measures were features associated with unsatisfactory positioning (Kakarla grades 1 and 2 vs Kakarla grade 3).RESULTSFifty-one EVDs (27%) were suboptimally positioned. Fifteen (8%) EVDs were placed into eloquent cortex or nontarget CSF spaces. Admitting diagnosis, head height-to-width ratio in axial plane, and side of predominant pathology were found to be significantly associated with suboptimal placement (p = 0.02, 0.012, and 0.02, respectively). A decreased height-to-width ratio was also associated with placement into only eloquent cortex and/or nontarget CSF spaces (p = 0.003).CONCLUSIONSFreehand insertion of an EVD is associated with significant suboptimal positioning into parenchyma and nontarget CSF spaces. The likelihood of inaccurate EVD placement can be predicted with baseline clinical and radiographic features. The patient’s height-to-width ratio represents a novel potential radiographic predictor for malpositioning.

OBJECTIVEReadmission to the hospital within 30 days of discharge is used as a surrogate marker for quality and value of care in the United States (US) healthcare system. Concern exists regarding the value of 30-day readmission as a quality of care metric in neurosurgical patients. Few studies have assessed 30-day readmission rates in neurosurgical patients outside the US. The authors performed a retrospective review of all adult neurosurgical patients admitted to a single Canadian neurosurgical academic center and who were discharged to home to assess for the all-cause 30-day readmission rate, unplanned 30-day readmission rate, and avoidable 30-day readmission rate.METHODSA retrospective review was performed assessing 30-day readmission rates after discharge to home in all neurosurgical patients admitted to a single academic neurosurgical center from January 1, 2011, to December 31, 2011. The primary outcomes included rates of all-cause, unplanned, and avoidable readmissions within 30 days of discharge. Secondary outcomes included factors associated with unplanned and avoidable 30-day readmissions.RESULTSA total of 184 of 950 patients (19.4%) were readmitted to the hospital within 30 days of discharge. One-hundred three patients (10.8%) were readmitted for an unplanned reason and 81 (8.5%) were readmitted for a planned or rescheduled operation. Only 19 readmissions (10%) were for a potentially avoidable reason. Univariate analysis identified factors associated with readmission for a complication or persistent/worsening symptom, including age (p = 0.009), length of stay (p = 0.007), general neurosurgery diagnosis (p < 0.001), cranial pathology (p < 0.001), intensive care unit (ICU) admission (p < 0.001), number of initial admission operations (p = 0.01), and shunt procedures (p < 0.001). Multivariate analysis identified predictive factors of readmission, including diagnosis (p = 0.002, OR 2.4, 95% CI 1.4–5.3), cranial pathology (p = 0.002, OR 2.7, 95% CI 1.4–5.3), ICU admission (p = 0.004, OR 2.4, 95% CI 1.3–4.2), and number of first admission operations (p = 0.01, OR 0.51, 95% CI 0.3–0.87). Univariate analysis performed to identify factors associated with potentially avoidable readmissions included length of stay (p = 0.03), diagnosis (p < 0.001), cranial pathology (p = 0.02), and shunt procedures (p < 0.001). Multivariate analysis identified only shunt procedures as a predictive factor for avoidable readmission (p = 0.02, OR 5.6, 95% CI 1.4–22.8).CONCLUSIONSAlmost one-fifth of neurosurgical patients were readmitted within 30 days of discharge. However, only about half of these patients were admitted for an unplanned reason, and only 10% of all readmissions were potentially avoidable. This study demonstrates unique challenges encountered in a publicly funded healthcare setting and supports the growing literature suggesting 30-day readmission rates may serve as an inappropriate quality of care metric in neurosurgical patients. Potentially avoidable readmissions can be predicted, and further research assessing predictors of avoidable readmissions is warranted.

OBJECTIVE. This systematic review and meta-analysis evaluates the diagnostic accuracy of MRI for differentiating malignant (MPNSTs) from benign peripheral nerve sheath tumors (BPNSTs). MATERIALS AND METHODS. A systematic review of MEDLINE, Embase, Scopus, the Cochrane Library, and the gray literature from inception to December 2019 was performed. Original articles that involved at least 10 patients and that evaluated the accuracy of MRI for detecting MPNSTs were included. Two reviewers independently extracted clinical and radiologic data from included articles to calculate sensitivity, specificity, PPV, NPV, and accuracy. A meta-analysis was performed using a bivariate mixed-effects regression model. Risk of bias was evaluated using QUADAS-2. RESULTS. Fifteen studies involving 798 lesions (252 MPNSTs and 546 BPNSTs) were included in the analysis. Pooled and weighted sensitivity, specificity, and AUC values for MRI in detecting MPNSTs were 68% (95% CI, 52-80%), 93% (95% CI, 85-97%), and 0.89 (95% CI, 0.86-0.92) when using feature combination and 88% (95% CI, 74-95%), 94% (95% CI, 89-96%), and 0.97 (95% CI, 0.95-0.98) using diffusion restriction with or without feature combination. Subgroup analysis, such as patients with neurofibromatosis type 1 (NF1) versus those without NF1, could not be performed because of insufficient data. Risk of bias was predominantly high or unclear for patient selection, mixed for index test, low for reference standard, and unclear for flow and timing. CONCLUSION. Combining features such as diffusion restriction optimizes the diagnostic accuracy of MRI for detecting MPNSTs. However, limitations in the literature, including variability and risk of bias, necessitate additional methodologically rigorous studies to allow subgroup analysis and further evaluate the combination of clinical and MRI features for MPNST diagnosis.

The objective of this study is to evaluate the diagnostic accuracy, interobserver variability, and common lexicon pitfalls of the ACR O-RADS scoring system among staff radiologists without prior experience to O-RADS. After independent review of the ACR O-RADS publications and 30 training cases, three fellowship-trained, board-certified staff radiologists scored 50 pelvic ultrasound exams using the O-RADS system. The diagnostic accuracy and area under receiver operating characteristic were analyzed for each reader. Overall agreement and pair-wise agreement between readers were also analyzed. Excellent specificities (92 to 100%), NPVs (92 to 100%), and variable sensitivities (72 to 100%), PPVs (66 to 100%) were observed. Considering O-RADS 4 and O-RADS 5 as predictors of malignancy, individual reader AUC values range from 0.94 to 0.98 (p

OBJECTIVE. This systematic review and meta-analysis aimed to evaluate the diagnostic accuracy of limited MRI protocols for detecting radiographically occult proximal femoral fractures. MATERIALS AND METHODS. A systematic review of MEDLINE, Embase, Scopus, the Cochrane Library, and the gray literature through November 15, 2019, was performed. Original articles with 10 or more patients evaluating limited MRI protocols for the diagnosis of radiographically occult proximal femoral fractures compared with multiparametric MRI with or without clinical outcome as the reference standard were included in the analysis. Patient, clinical, MRI, and performance parameters were independently acquired by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model. RESULTS. Eleven studies with 938 patients and 247 proximal femoral fractures met inclusion criteria, and five of these studies were included in the meta-analysis. The pooled and weighted summary sensitivity and specificity and the area under the summary ROC curve for limited MRI protocols in detecting radiographically occult hip fractures were 99% (95% CI, 91-100%), 99% (95% CI, 97-100%), and 1 (95% CI, 0.99-1), respectively. The aggregate sensitivity and specificity values for a single-plane T1-weighted sequence only, STIR sequence only, T1-weighted and STIR sequences, and T2-weighted sequence only were as follows: 97% (89/92) and 100% (76/76), 99% (126/127) and 99% (865/873), 100% (118/118) and 99% (867/874), and 86% (51/59) and 97% (137/141), respectively. Sensitivity was 100% (58/58) when images were acquired on 3-T scanners only and 99% (284/288) when interpreted only by certified radiologists. The mean scanning time for the limited MRI protocols was less than 5 minutes. CONCLUSION. Limited MRI protocols can be used as the standard of care in patients with a suspected but radiographically occult hip fracture. A protocol composed of coronal T1-weighted and STIR sequences is 100% sensitive.

Purpose This scoping review evaluated the currently available data related to abdominal imaging in the SARS-CoV-2 infection. Method A systematic review of MEDLINE, EMBASE, SCOPUS, and Web of Science was performed from inception to July 15, 2020 using PRISMA-ScR guidelines. The review included case reports and series discussing radiologic manifestations of SARS-CoV-2 infection in abdominal imaging studies. Studies published from inception to March 31, 2020, were independently screened and reviewed by one author, and another author reviewed studies published after March 31 to July 15, 2020. Study screening and full-text review for publications before March 31, 2020, was performed by one author, and another author for publications after March 31 to July 15, 2020. Results Thirty-six studies were included in qualitative synthesis. The prevalence of gastrointestinal symptoms is roughly 18% and includes loss of appetite, nausea, vomiting, diarrhea, and abdominal pain. Sixteen percent of COVID-19 cases may only present with gastrointestinal symptoms. Many patients presenting this way demonstrate evidence of COVID-19 incidentally through abdominal CT imaging at the lung bases. Studies published to date have also reported abdominal imaging findings including small and large bowel wall thickening, fluid-filled colon, pneumatosis intestinalis, pneumoperitoneum, intussusception, and ascites. Conclusion Gastrointestinal manifestations and imaging manifestations of SARS-CoV-2 infection are increasingly reported and warrant specific attention during abdominal imaging. Electronic supplementary material The online version of this article (10.1007/s00261-020-02739-5) contains supplementary material, which is available to authorized users.

Lipid-poor angiomyolipomas (lpAMLs) constitute up to 5% of renal angiomyolipomas and are challenging to differentiate from malignant renal lesions on imaging alone. This review aims to identify clinical and MRI features which can be utilized to improve specificity and diagnostic accuracy for detecting lpAMLs in patients being considered for active surveillance rather than intervention. Young age, female sex, and small lesion size are associated with lpAMLs in studies evaluating indeterminate renal lesions. The accuracy of criteria using T2-weighted imaging, diffusion-weighted imaging, chemical shift imaging, dynamic contrast enhancement, multiparametric imaging, and radiomics are reviewed. Low T2 signal intensity is a particularly important MRI feature for lpAML. In studies with low T2 signal intensity, homogeneous early enhancement is a typical feature with an arterial-to-delay enhancement ratio > 1.5. Intratumoral hemorrhage with decrease in signal intensity on in-phase chemical shift imaging may be particularly useful for differentiating papillary renal cell carcinomas from lpAMLs in low T2 signal intensity lesions. Combining clinical and multiparametric MRI features can result in near-perfect specificity for lpAML. In select patients, clinical and MRI features can result in a high specificity and diagnostic accuracy for lpAMLs. These lesions can be considered for active surveillance rather than invasive diagnostic and therapeutic procedures such as biopsy or surgery.

BACKGROUND AND PURPOSE: The superior diagnostic accuracy of fetal MR imaging in detecting fetal brain abnormalities has been previously demonstrated; however, the ability of fetal MR imaging to prognosticate postnatal outcome is not well-studied. We performed a retrospective analysis to determine the prognostic accuracy of fetal MR imaging in predicting postnatal neurodevelopmental outcome. MATERIALS AND METHODS: We identified all fetal MR imaging performed at the Children9s Hospital of Eastern Ontario during a 10-year period and assessed agreement between prenatal prognosis and postnatal outcome. Prenatal prognosis was determined by a pediatric neurologist who reviewed the fetal MR imaging report and categorized each pregnancy as having a favorable, indeterminate, or poor prognosis. Assessment of postnatal neurodevelopmental outcome was made solely on the basis of the child’s Gross Motor Function Classification System score and whether the child developed epilepsy. Postnatal outcome was categorized as favorable, intermediate, or poor. We also assessed the diagnostic accuracy of fetal MR imaging by comparing prenatal and postnatal imaging diagnoses. RESULTS: We reviewed 145 fetal MR images: 114 were included in the assessment of diagnostic accuracy, and 104 were included in the assessment of prognostic accuracy. There was 93.0% agreement between prenatal and postnatal imaging diagnoses. Prognosis was favorable in 44.2%, indeterminate in 50.0%, and poor in 5.8% of pregnancies. There was 93.5% agreement between a favorable prenatal prognosis and a favorable postnatal outcome. CONCLUSIONS: A favorable prenatal prognosis is highly predictive of a favorable postnatal outcome. Further studies are required to better understand the role of fetal MR imaging in prognosticating postnatal development, particularly in pregnancies with indeterminate and poor prognoses.

Introduction The purpose of this systematic review and meta-analysis was to evaluate the diagnostic accuracy of liver and spleen stiffness on magnetic resonance elastography (MRE) for detecting clinically significant portal hypertension. Methods A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the Grey Literature through to 15 August 2019 was performed. Original articles with >10 patients evaluating liver and/or spleen stiffness on MRE using a reference standard of portal hypertension defined as intractable ascites, esophageal varices, encephalopathy and/or death were included in analysis. Patient, clinical, MRI, and diagnostic performance was independently acquired by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model. Results Fourteen studies were included with 12 studies evaluating liver stiffness and eight studies evaluating spleen stiffness. The pooled and weighted sensitivity, specificity, and area under the curve (AUC) values for liver stiffness on MRE were 83% [95% confidence interval (CI) 72-90%], 80% (95% CI 70-88%), and 88% (95% CI 85-91%), respectively. The pooled and weighted sensitivity, specificity, and AUC values for spleen stiffness on MRE were 79% (95% CI 61-90%), 90% (95% CI 80-95%), and 92% (95% CI 89-94%), respectively. The liver and spleen stiffness sensitivity and specificity values were comparable when evaluating for esophageal varices only at of 80% (95% CI 66-89%) and 76% (95% CI 62-86%) for liver stiffness, and 75% (95% CI 52-90%) and 89% (95% CI 70-96%) for spleen stiffness. Discussion Liver and spleen stiffness on MRE can serve as a supplemental noninvasive assessment tools for detecting clinically significant portal hypertension. Spleen stiffness may be more specific and accurate than liver stiffness for detecting portal hypertension.

This meta-analysis evaluated the diagnostic accuracy of dual-energy CT (DECT) for detecting bone marrow edema (BME) in the appendicular skeleton. A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and gray literature from inception through January 31, 2020, was performed. Original articles with > 10 patients evaluating the accuracy of DECT for detecting BME in the appendicular skeleton with a reference standard of MRI and/or clinical follow-up were included. Study details were independently extracted by two reviewers. Meta-analysis was performed using a bivariate random-effects model with multivariable meta-regression. Risk of bias (RoB) was evaluated with QUADAS-2. Twenty studies evaluating 790 patients for BME in the appendicular skeleton were included in analysis. The summary sensitivity, specificity, and AUC values for BME in the appendicular skeleton were 86% (95% confidence interval [CI] 82–89%), 93% (95% CI 90–95%), and 0.95, respectively. Quantitative analysis had a higher sensitivity than qualitative analysis on meta-regression (p = 0.01), but no difference in specificity (p = 0.28). No other covariates contributed to variability in accuracy (etiology (trauma vs non-trauma); location (upper vs lower extremity); and RoB). Studies demonstrated generally low or unclear RoB and applicability. Eight studies included index tests with high RoB when quantitative assessments used a retrospective cut-off value. DECT demonstrates a higher specificity than sensitivity and AUC > 0.9. In scenarios where MRI availability is limited or contraindicated, DECT could be an alternative to MRI for detecting BME in the appendicular skeleton. However, limitations in sources of variability and RoB warrant continued study. • Twenty studies evaluating 790 patients for bone marrow edema in the appendicular skeleton with dual-energy CT were included in analysis. • The summary sensitivity, specificity, and AUC values for detecting bone marrow in the appendicular skeleton were 86% (95% confidence interval [CI] 82–89%), 93% (95% CI 90–95%), and 0.95, respectively. • In scenarios where MRI availability is limited or is contraindicated, DECT could be an alternative to MRI for detecting bone marrow edema in the appendicular skeleton.

Imaging features of benign mixed Brenner tumor and mucinous cystadenomas are rarely reported. This report aims to describe the case of a benign mixed Brenner tumor and mucinous cystadenoma with a dominant Brenner tumor component and to review the typical imaging features of this ovarian neoplasm.

BackgroundOptimal technical approaches of large-vessel anterior circulation acute ischemic strokes with concomitant extracranial internal carotid artery tandem occlusions is controversial.PurposeThis systematic review and meta-analysis evaluates: the overall outcomes of patients with tandem occlusions treated with second-generation mechanical thrombectomy devices; differences in outcomes of extracranial versus intracranial first approaches; and differences in outcomes of extracranial stenting at time of procedure versus angioplasty alone.MethodsMEDLINE, EMBASE, and the Web of Science was searched through September 2017 for studies evaluating patients presenting with acute tandem occlusions of the extracranial ICA and intracranial ICA, and/or proximal MCA treated with second-generation mechanical thrombectomy devices. Outcomes were pooled across studies using the random-effects model and expressed as cumulative incidence (event rate) and 95% CI.ResultsThirty-three studies were included in analysis. Overall mRS≤0–2 at 90 days was 47% (95% CI 42% to 51%). No statistical difference was seen in 90-day mRS≤0–2 for patients treated with extracranial versus intracranial first approaches, 53% (95% CI 44% to 61%) vs 49% (95% CI 44% to 57%) (P=0.58). No statistical difference was seen in 90-day mRS≤0–2 for patients treated with extracranial stenting versus angioplasty alone, 49% (95% CI 42% to 56%) vs 49% (95% CI 33% to 65%) (P=0.39). No other statistical differences in outcome or safety were identified.ConclusionsNearly half of all tandem occlusion patients treated with mechanical thrombectomy have good neurological outcomes. No statistical differences in outcome are identified between extracranial first versus intracranial first approaches, nor extracranial stenting versus angioplasty alone.

Background Optimal surgical management for flexion-distraction cervical spine injuries remains controversial with current guidelines recommending anterior, posterior, and circumferential approaches. Here, we determined the incidence of and examined risk factors for clinical and radiographic failure in patients with 1-segment cervical distraction injuries having undergone anterior surgical fixation. Methods A retrospective review of 57 consecutive patients undergoing anterior fixation for subaxial flexion-distraction cervical injuries between 2008 and 2012 at our institution was performed. The primary outcome was the number of patients requiring additional surgical stabilization and/or radiographic failure. Data collected included age, gender, mechanism and level of injury, facet pattern injury, and vertebral end plate fracture. Results A total of 6 patients failed clinically and/or radiographically (11%). Four patients (7%) required additional posterior fixation. Although 2 other patients identified met radiographic failure criteria, at follow-up they had fused radiographically, were stable clinically, and no further treatment was pursued. Progressive kyphosis and translation were found to be significantly correlated with need for revision ( P P = 0.02, respectively). No differences were identified for all other clinical and radiologic factors assessed, including unilateral or bilateral facet injury, facet fracture, and end plate fracture. Conclusion This study contributes to the growing body of evidence supporting anterior fixation alone for flexion-distraction injuries. Findings suggest that current measurements of radiographic failure including segmental translation and kyphosis may predict radiographic failure and need for further surgical stabilization in some patients. Future follow-up studies assessing for independent risk factors for anterior approach failure with a validated predictive scoring model should be considered.

KEY POINTS A 55-year-old woman with a history of hypertension, fibromuscular dysplasia and previous stroke presented to our family practice clinic with a 4-day history of nonexertional chest pain. It started as acute left-sided pleuritic chest pain that radiated into the neck with associated

Acute hemorrhagic presentation in pilocytic astrocytomas (PAs) has become increasingly recognized. This type of presentation poses a clinically emergent situation in those hemorrhages arising in PAs of the cerebellum, the most frequent site, because of the limited capacity of the posterior fossa to compensate for mass effect, predisposing to rapid neurological deterioration. As examples, we describe two cases of fatal hemorrhagic cerebellar PAs: one of a child with a slowly growing stereotypical WHO Grade I PA with a 1-year period of symptomatology that preceded a rapid clinical deterioration, and another of an asymptomatic child having a PA variant, presenting with progressive obtundation following a presumed Valsalva event. These two scenarios parallel previous reports in the literature of either a setting of progressive expression of cerebellar dysfunction and transient episodes of raised intracranial pressure (ICP), or abrupt onset of features of increased ICP in a previously well child. The literature is further reviewed for a current understanding of the factors that predispose, initiate and propagate bleeding, with specific reference to the role of vascular endothelial growth factor and other angiogenic agents in the genesis and stability of the vasculature in PAs. In this context, we propose that obliterative vascular mural hyalinization with associated altered flow dynamics and microaneurysm formation was the pathogenesis of the hemorrhage in our first case. In the second case, large tumor size, increased growth rate, looseness of the background myxoid matrix, and thinness of the tumor blood vessels with calcospherite deposition predisposed to vascular leakage and bleeding concurrent with sudden increases in intravascular hydrostatic pressure. In that cerebellar PAs are common, this report underscores the importance of considering in the differential diagnosis the possibility of a spontaneous hemorrhage in a posterior fossa PA in a child presenting with a sudden neurological ictus and raised ICP.

We enjoyed reading Povleson et al.'s review entitled "Diagnostic thoracic outlet syndrome: current approaches and future directions" [...].

Context The stool softener docusate is widely used in the management of constipation in hospice patients. There is little experimental evidence to support this practice, and no randomized trials have been conducted in the hospice setting. Objectives To assess the efficacy of docusate in hospice patients. Methods This was a 10-day, prospective, randomized, double-blind, placebo-controlled trial of docusate and sennosides vs. placebo and sennosides in hospice patients in Edmonton, Alberta. Patients were included if they were age 18 years or older, able to take oral medications, did not have a gastrointestinal stoma, and had a Palliative Performance Scale score of 20% or more. The primary outcome measures were stool frequency, volume, and consistency. Secondary outcomes were patient perceptions of bowel movements (difficulty and completeness of evacuation) and bowel-related interventions. Results A total of 74 patients were randomized into the study (35 to the docusate group and 39 to the placebo group). There were neither significant differences between the groups in stool frequency, volume, or consistency, nor in difficulty or completeness of evacuation. On the Bristol Stool Form Scale, more patients in the placebo group had Type 4 (smooth and soft) and Type 5 (soft blobs) stool, whereas in the docusate group, more had Type 3 (sausage like) and Type 6 (mushy) stool (P=0.01). Conclusion There was no significant benefit of docusate plus sennosides compared with placebo plus sennosides in managing constipation in hospice patients. Docusate use should be considered on an individual basis.

Spinal arteriovenous malformations are rare in children, although perimedullary arteriovenous fistulas (PMAVFs) may account for up to 24% of spinal arteriovenous malformations in this age group. Reported presentations of PMAVFs have included progressive or acute myelopathic symptoms, pain, hematomyelia, and subarachnoid hemorrhage. No known reports of an unruptured PMAVF causing communicating hydrocephalus have been previously published. A 17-month-old girl presented to the authors' clinic with a 6-month history of back and leg pain, gait regression, constipation, and marked lumbar hyperlordosis due to a PMAVF. A brain MRI study also demonstrated advanced hydrocephalus. The patient underwent embolization with Onyx of 2 feeding arteries from the right L-1 and 1 feeding artery from the left L-1 lumbar arteries. Postembolization follow-up imaging demonstrated a reduction in size of the L-1 pedicles and no residual supply of the fistula. Three-year clinical follow-up showed normal bowel and bladder function with significant improvements in the patient's back pain, gait, and hyperlordosis. The patient's ventricular enlargement improved without direct management of her hydrocephalus. To the authors' knowledge, this is the first reported case of communicating hydrocephalus caused by an unruptured PMAVF. The authors postulate that the origin of hydrocephalus was either central venous hypertension caused by the high-flow fistula or a change in fluid dynamics reducing CSF resorption through arachnoid granulations in the lumbar region of the spinal cord. The exact role that spinal arachnoid granulations play in CSF resorption is not currently known. Regardless of pathogenesis, initial treatment should focus on management of the fistula with additional hydrocephalus management only when necessary.

On November 17, 2011 I had the great pleasure of presenting to some 200 students, parents, and faculty at the first every University of Alberta Undergraduate Research Symposium. This Letter to the Editor addresses my discussion on the many positive aspects of undergraduate research to students considering involvement that are often under-presented. Beyond the assigned research, multiple potentially beneficial opportunities exist including course/elective credit, monetary remuneration, development of contacts and references, academic and personal development, and more. In addition, this letter highlights new initiatives at the University of Alberta as well as showcasing the excellence of research that is presently being performed by students at our institution.